One electrophotographic color printer well known in the art is a tandem color laser printer equipped with four developer cartridges accommodating toner in the respective colors yellow, magenta, cyan, and black; and four photosensitive drums corresponding to these developer cartridges. The printer can switch between a monochrome mode for forming images in black by keeping the developer cartridge for black in contact with the photosensitive drums while separating the non-black developer cartridges from their photosensitive drums, and a color mode for forming color images by placing all developer cartridges in contact with their respective photosensitive drums.
One such tandem color laser printer includes four photosensitive drums, a belt unit having an endless belt disposed so as to confront the four photosensitive drums, and a cleaning unit for cleaning residual toner deposited on the endless belt. The cleaning unit includes a blade and roller for recovering toner from the endless belt, and a cleaning box for storing the recovered toner.